package com.century.sjt.util;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

/**
 * Created by luodong on 15/12/29.
 */
public class CompressUtil {
    //压缩图片
    public static Bitmap compressImg(String pathName){
        Bitmap bitmap=null;
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(pathName, options);
        // 源图片的宽度
        //int width = options.outWidth;
//        options.inSampleSize = calculateInSampleSize(options, 1600);            //限定为1600像素
        options.inSampleSize = computeSampleSize(options, -1, 1000 * 1000);
        options.inJustDecodeBounds = false;
        try{
            bitmap= BitmapFactory.decodeFile(pathName, options);
        }catch (Exception e){

        }
        return bitmap;
    }


    private static int computeSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) {
        int initialSize = computeInitialSampleSize(options, minSideLength, maxNumOfPixels);
        int roundedSize;
        if (initialSize <= 8) {
            roundedSize = 1;
            while (roundedSize < initialSize) {
                roundedSize <<= 1;
            }
        } else {
            roundedSize = (initialSize + 7) / 8 * 8;
        }
        return roundedSize;
    }

    private static int computeInitialSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) {
        double w = options.outWidth;
        double h = options.outHeight;
        int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));
        int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(Math.floor(w / minSideLength), Math.floor(h / minSideLength));
        if (upperBound < lowerBound) {
            // return the larger one when there is no overlapping zone.
            return lowerBound;
        }
        if ((maxNumOfPixels == -1) && (minSideLength == -1)) {
            return 1;
        } else if (minSideLength == -1) {
            return lowerBound;
        } else {
            return upperBound;
        }
    }

    //裁剪图片为正方形
    public static Bitmap centerSquareScaleBitmap(Bitmap bitmap, int edgeLength)
    {
        if(null == bitmap || edgeLength <= 0)
        {
            return  null;
        }

        Bitmap result = bitmap;
        int widthOrg = bitmap.getWidth();
        int heightOrg = bitmap.getHeight();

        if(widthOrg > edgeLength && heightOrg > edgeLength)
        {
            //压缩到一个最小长度是edgeLength的bitmap
            int longerEdge = (int)(edgeLength * Math.max(widthOrg, heightOrg) / Math.min(widthOrg, heightOrg));
            int scaledWidth = widthOrg > heightOrg ? longerEdge : edgeLength;
            int scaledHeight = widthOrg > heightOrg ? edgeLength : longerEdge;
            Bitmap scaledBitmap;

            try{
                scaledBitmap = Bitmap.createScaledBitmap(bitmap, scaledWidth, scaledHeight, true);
            }
            catch(Exception e){
                return null;
            }

            //从图中截取正中间的正方形部分。
            int xTopLeft = (scaledWidth - edgeLength) / 2;
            int yTopLeft = (scaledHeight - edgeLength) / 2;

            try{
                result = Bitmap.createBitmap(scaledBitmap, xTopLeft, yTopLeft, edgeLength, edgeLength);
                scaledBitmap.recycle();
            }
            catch(Exception e){
                return null;
            }
        }

        return result;
    }

}
